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Math 3081 (Probability and Statistics), Summer-II 2021



Course Information
Instructor Class Times Office Hours
Evan Dummit
edummit at northeastern dot edu
(Section 1) MTWR, 1:30pm-3:10pm
(Section 2) MTWR, 9:50am-11:30am
Online, via Zoom
M 3:15pm-4:30pm
R 3:15pm-4:30pm
or by appointment
Online, via Zoom
There are two sections of Math 3081, corresponding to the two lecture times listed. The lectures will cover the same material at the same pace. All lectures will be recorded and made available for on-demand viewing at any time.
Math 3081 uses a Piazza page for course discussion. Links to all of the live lectures, office hours, problem sessions, and lecture recordings are hosted there.
Teaching Assistant Recitation Time Office Hours
Jiewei Feng
feng.ji at northeastern dot edu
R noon-1pm
Online, via Zoom
T 3:30pm-4:30pm
Online, via Zoom
For detailed information about the course, please consult the 3081 Course Syllabus. (Note: any information given in class or on this webpage supersedes the written syllabus.)
All homework assignments are available on the 3081 WeBWorK page. To create your initial login, follow the Rederly signup link posted on the 3081 Canvas page (you must use your Northeastern email address).


Handouts / Lecture Notes
The instructor will write lecture notes for the course in place of an official textbook as the semester progresses. The course will follow the presentation in Larsen and Marx's "An Introduction to Mathematical Statistics and its Applications" (5th edition), but it is not necessary to purchase the textbook for this course.

For those students who are using the textbook, here are the correspondences between the notes and textbook:
Notes ch1: Book §2.1-2.7 (Probability)
Notes ch2: Book §3.1-3.9 + §4.1-4.3 (Random Variables)
Notes ch3: Book §5.1-5.4 (Parameter Estimation)
Notes ch4: Book §6.1-6.4 + §7.1-7.5 (Hypothesis Testing)
Notes ch5: Book §9.1-9.5 + §10.1-10.4 (Topics in Hypothesis Testing)
Handout Topics
Chapter 1: Counting and Probability (25pp, v2.50, posted 6/29) 1.1 ~ Sets and Set Operations
1.2 ~ Counting Principles
1.3 ~ Probability and Probability Distributions
1.4 ~ Conditional Probability and Independence
Chapter 2: Random Variables (36pp, v2.50, posted 7/9) 2.1 ~ Discrete Random Variables
2.2 ~ Continuous Random Variables
2.3 ~ The Normal Distribution, Central Limit Theorem, and Modeling Applications
Chapter 3: Parameter and Interval Estimation (18pp, v2.00, posted 7/24) 3.1 ~ Parameter Estimation
3.2 ~ Interval Estimation
Chapter 4: Hypothesis Testing (21pp, v2.00, posted 8/1) 4.1 ~ Principles of Hypothesis Testing
4.2 ~ One-Sample and Two-Sample z Tests
4.3 ~ Errors and Misinterpretations of Hypothesis Testing
Chapter 5: Topics in Hypothesis Testing (31pp, v2.00, posted 8/7) 5.1 ~ The t Distribution and t Tests
5.2 ~ The χ2 Distribution and χ2 Tests


Lecture Slides
These are the slides used during the lectures. They will usually be posted ahead of the lecture time.
Date Material
Mon, Jul 5th
Tue, Jul 6th
Wed, Jul 7th
Thu, Jul 8th
University holiday; no classes
Lecture 1: Welcome + Sets and Counting (Notes 1.1-1.2.1) [typos fixed]
Lecture 2: Permutations and Combinations, Sample Spaces (Notes 1.2.2-1.3.1)
Lecture 3: Probability (Notes 1.3.2-1.3.3)
Mon, Jul 12th
Tue, Jul 13th
Wed, Jul 14th
Thu, Jul 15th
Lecture 4: Conditional Probability and Independence (Notes 1.3.3-1.4.1)
Lecture 5: Computing Probabilities (Notes 1.4.2-1.4.3)
Lecture 6: Bayes' Theorem + Discrete Random Variables (Notes 1.4.3 + 2.1.1-2.1.2)
Lecture 7: Discrete Random Variables, Part 2 (Notes 2.1.3-2.1.5)
Mon, Jul 19th
Tue, Jul 20th
Wed, Jul 21st
Thu, Jul 22nd
Lecture 8: Discrete Random Variables, Part 3 (Notes 2.1.5-2.2.2)
Lecture 9: Continuous Random Variables, Part 1.5 (Notes 2.2.1-2.2.2)
Lecture 10: Continuous Random Variables, Part 2.5 (Notes 2.2.2-2.2.3) [updated]
Lecture 11: Continuous Random Variables, Part 3.5 + Normal Distributions (Notes 2.2.4-2.3.2)
Mon, Jul 26th
Tue, Jul 27th
Wed, Jul 28th
Thu, Jul 29th
Lecture 12: The Central Limit Theorem and Applications (Notes 2.3.2-2.3.3)
Lecture 13: Poisson + Exponential Applications (Notes 2.3.3-2.3.4)
Lecture 14: Maximum Likelihood Estimates (Notes 3.1.1-3.1.2)
Lecture 15: Bias and Efficiency of Estimators (Notes 3.1.2-3.1.3)
Mon, Aug 2nd
Tue, Aug 3rd
Wed, Aug 4th
Thu, Aug 5th
Lecture 16: Confidence Intervals, Part 1 (Notes 3.2.1-3.2.2)
Lecture 17: Confidence Intervals, Part 2 (Notes 3.2.2-3.2.3)
Lecture 18: Hypothesis Testing, z-Tests (Notes 4.1.1-4.2.1) [typos fixed]
Lecture 19: More z-Tests (Notes 4.2.1-4.2.3)
Mon, Aug 9th
Tue, Aug 10th
Wed, Aug 11th
Thu, Aug 12th
Lecture 20: Unknown Proportion + Errors in Hypothesis Testing (Notes 4.2.3-4.3.1)
Lecture 21: Errors and Misuses of Hypothesis Testing (Notes 4.3.1-4.3.2)
Lecture 22: The t Distribution and Confidence Intervals (Notes 5.1.1-5.1.2)
Lecture 23: One-Sample t Tests (Notes 5.1.3-5.1.4)
Mon, Aug 16th
Tue, Aug 17th
Wed, Aug 18th
Thu, Aug 19th
Lecture 24: Two-Sample t Tests (Notes 5.1.4)
Lecture 25: Matched Pairs + Robustness of t Tests (Notes 5.1.4-5.1.5)
Lecture 26: The χ2 Distribution and Confidence Intervals (Notes 5.2.1-5.2.3)
Lecture 27: The χ2 Tests for Goodness of Fit and Independence (Notes 5.2.3-5.2.4)


Problem Sheets
These are the problem sheets for the course's problem sessions, held each week on Thursday.
Date Material
Thu, Jul 8th Session 1 (Sets, Counting, and Probability): Sheet 1, Sheet 1a
Thu, Jul 15th Session 2 (Probability and Discrete Random Variables): Sheet 2
Thu, Jul 22nd Session 3 (Discrete and Continuous Random Variables): Sheet 3
Thu, Jul 29th Session 4 (Continuous Variables, Normal, Exponential, Poisson): Sheet 4
Thu, Aug 5th Session 5 (MLEs, Bias + Efficiency, Confidence Intervals): Sheet 5
Thu, Aug 12th Session 6 (Hypothesis Tests, z tests, Type I/II Errors, Power): Sheet 6
Thu, Aug 19th Session 7 (t and χ2 Tests + Confidence Intervals): Sheet 7


Exam Information
Exams will be distributed and collected via the 3081 Canvas page. You will download the exam file, take it, and then upload scans of your exam responses during your testing window.
Exam Date, Time, Location Topics Review Material
Exam 1
(Form A), (sols)
(Form B), (sols)
Sat, Jul 17th
Via Canvas
Lectures 1-7
WeBWorKs 1-2
Notes §1.1-1.4 + §2.1.1-2.1.3
Review Problems (answers)
Review session Fri Jul 16th, 1pm-3pm
Exam 2
(Form A), (sols)
(Form B), (sols)
Sat, Jul 31st
Via Canvas
Lectures 8-14
WeBWorKs 3-4
Notes §2.1-2.3
Review Problems (answers)
Review session Fri Jul 30th, 1pm-3pm
Exam 3
(Form A), (sols)
(Form B), (sols)
Sat, Aug 14th
Via Canvas
Lectures 15-22
WeBWorKs 5-6
Notes §3.1-3.2 + §4.1-4.2.2 + §5.1.-5.1.2
Review Problems (answers)
Review session Fri Aug 13th, 1pm-3pm
Final Mon, Aug 23rd or
Tue, Aug 24th
Via Canvas
Comprehensive:
Lectures 1-27
WeBWorKs 1-7
Notes §1.1-5.2
Short:
Lectures 23-27
WeBWorK 7
Notes §5.1-5.2
Review Problems (answers)
Review sessions Sat Aug 21st + Sun Aug 22nd, times TBA
For exams, you are permitted one "cheat sheet", consisting of a single-sided 8.5in-by-11in piece of paper. Calculators are permitted, but cell phones, other electronic devices, books, and additional notes of any kind will NOT be permitted in exams.


Old Exams
These are exams from previous Math 3081 courses, and are provided to give you an additional source of practice problems. Please note: some courses may have been organized differently than this course, so some material may differ from exam to exam. Some topics from our course may be covered or emphasized differently, or skipped altogether, and some topics on these exams may not appear on the exams in this course.
Exam 1 Exam 2 Exam 3 Final Exam
2018 Summer 1 (with solutions)

2019 Summer 2, (solutions)
2018 Summer 1, (solutions)

2019 Summer 2, (solutions)
2018 Summer 1, (solutions)

2019 Summer 2, (solutions)
2017 Spring, (solutions)

2017 Spring, (solutions)

2017 Spring, (solutions)

2017 Summer 2 (with solutions)

2018 Spring, (solutions)

2018 Summer 1, (solutions)


Tips For Success In This Course
Attend Lecture Missing lecture is a bad idea! If for any reason you cannot make it to a class, you should watch the recording of the lecture. You are responsible for all material covered in lecture.
Read the Lecture Notes (or Textbook) The lecture notes and the textbook are comprehensive sources of material for the course. The notes are intended as review material, although many students like to read them as preparation before attending the lecture on the corresponding topics. Please note that the electronic notes are not identical to the material covered in class: this is by design, so as to provide you a slightly different perspective on the material.
Use WeBWorK Effectively WeBWorK assignments are intended to help you learn the course material at a basic level. Look over the problems well before the due date, and work on them in concert with the corresponding lectures. You may use technology (calculators, Wolfram Alpha, computer software) and other people to help you (so long as you are submitting your own work), but be mindful: if you do not understand how to do the WeBWorK problems, you will almost certainly struggle on the exams! (Exam problems are often harder than WeBWorK problems.)
Attend Office Hours Office hours are specifically reserved for you to receive individual, one-on-one help from the instructor or TAs. Office hours will be the most effective when you have already put in effort to learn the material on your own (including trying to solve the homework problems), and when you come in with a list of specific questions or topics you are struggling with.
Use Tutoring Services The university offers a wide variety of free tutoring services. Over the summer, the Tutoring Center is open for students taking various math courses, including Math 3081.


Course Schedule
The schedule is subject to change! All sections refer to the course lecture notes.
Week Schedule
Week of July 5
(class starts 7/6)
§1.1: Sets and Set Operations
§1.2: Counting Principles
§1.3: Probability and Probability Distributions
§1.4.1: Conditional Probability
WeBWorK 1 due Sunday 7/11 at 5am Eastern.
Week of July 12 §1.4.2: Independence
§1.4.3: Computing Probabilities, Bayes' Formula
§2.1.1: Discrete Random Variables
§2.1.2: Expected Value
§2.1.3: Variance and Standard Deviation
WeBWorK 2 due Friday 7/16 at 5am Eastern.
Review for Exam 1
EXAM 1 Saturday, July 17th (via Canvas)
Week of July 19 §2.1.4: Joint Distributions
§2.1.5: Independence
§2.1.6: Covariance and Correlation
§2.2: Continuous Random Variables
§2.3.1: The Normal Distribution
WeBWorK 3 due Friday 7/23 at 5am Eastern.
Week of July 26
§2.3.2: The Central Limit Theorem
§2.3.3: The Poisson Distribution and Poisson Limit Theorem
§2.3.4: The Exponential Distribution and Memoryless Processes
§3.1.1: Maximum Likelihood Estimates
§3.1.2: Biased and Unbiased Estimators
WeBWorK 4 due Friday 7/30 at 5am Eastern.
Review for Exam 2
EXAM 2 Saturday, July 31st (via Canvas)
Week of August 2 §3.1.3: Efficiency of Estimators
§3.2.1: Confidence Intervals
§3.2.2: Normal Confidence Intervals
§4.1: Hypothesis Testing
§4.2.1: One-Sample z Tests
§4.2.2: Two-Sample z Tests
WeBWorK 5 due Friday 8/6 at 5am Eastern.
Week of August 9 §4.1.3: z Tests for Unknown Proportion
§4.3.1: Type I and Type II Errors
§4.3.2: Misinterpretations and Misuses of Hypothesis Testing
§5.1.1: The t Distributions
§5.1.2: Confidence Intervals Using t Statistics
§5.1.3: One-Sample t Tests
WeBWorK 6 due Friday 8/13 at 5am Eastern.
Review for Exam 3
EXAM 3 Saturday, August 14th (via Canvas)
Week of August 16 (class ends 8/19)
§5.1.4: Two-Sample t Tests
§5.1.5: Robustness of t Tests
§5.2.1: The χ2 Distributions
§5.2.2: χ2 Confidence Intervals and Hypothesis Tests
§5.2.3: The χ2 Test for Independence
§5.2.4: The χ2 Test for Goodness of Fit
WeBWorK 7 due Friday 8/20 at 5am Eastern.
Review for Final Exam
Week of August 17
FINAL EXAM Monday, August 23rd or Tuesday, August 24th (via Canvas)